February 25, 2009 | | Comments 24
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Ahh, the fact and fiction about blanket warmer temperatures

The idea of blanket warmer temperatures is a fairly simple proposition that has swelled in importance far beyond its likely impact on patient care. This is partially because of some data-driven recommendations, but also because of certain assumptions made by The Joint Commission’s surveyor cadre.

There’s no nationally recognized standard for blanket warmer temperatures, which leaves it all to you to appropriately manage said temps. So that’s the assumption piece. You can fill in your own humorous aside relative to the merits and results of assuming.

Where things get a little more complicated is back in 2006 when the ECRI Institute issued a device alert regarding the hazards of storing things (blankets, fluids) in blanket warmers at what ECRI identified as excessive temperatures (104° F for fluids and 110° F for blankets). La Corporation des infirmières et infirmiers de salle d’opération du Québec has posted a copy of the alert on its Web site.

One of ECRI’s suggestions was for periodic monitoring of temperatures in applicable devices, particularly ones that cannot be set to a specific temperature.

At some point after the issuance of the device alert, the Association of Perioperative Registered Nurses reviewed the tenets of the alert and advised that organizations follow the recommendations for temperature settings. So that, if you will, is where the science of the thing comes into play.

Where this loops around on itself (and potentially around your jugular) during survey is The Joint Commission’s stance on what can nominally be identified as a best practice and the subsequent “requirement” for organizations to either:

  • Adopt whatever practice one might be discussing
  • Conduct a documented risk assessment that provides validation that the adopted alternative strategy should be considered equivalent

Ultimately, the risk involved with the blanket warmers is either destabilization of the product or burning someone by placing a too-hot item on the skin. If you look at the wording of the ECRI alert, the common descriptor is “ensure.” That’s the key idea when it comes to monitoring — how do you ensure that materials are maintained at an appropriate temperature? It’s all about making sure that the equipment you are using does just that, and you get to decide how that determination happens.

I have a sneaking suspicion that this is going to keep coming up in surveys of organizations that have not worked this through. This all folds back under EC.02.01.01, EP 2 (the hospital takes action to minimize or eliminate identified safety and security risks in the physical environment). That leaves things wide open for all manner of interpretive dance on the part of the surveyors, unless you can demonstrate that you’ve eliminated the risk or reduced the risk to its lowest potential. This goal becomes even more challenging if you choose not to adopt a best practice without conducting a risk assessment that speaks to the risk level.

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Filed Under: Environment of care


Steve MacArthur About the Author: Steve MacArthur is a safety consultant with The Greeley Company in Danvers, Mass. He brings more than 30 years of healthcare management and consulting experience to his work with hospitals, physician offices, and ambulatory care facilities across the country. He is the author of HCPro's Hospital Safety Director's Handbook and is contributing editor for Briefings on Hospital Safety. Contact Steve at stevemacsafetyspace@gmail.com.

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  1. Thanks for your research on many issues which often clarifys the intent of standards and to use as a training tool for our teams at Memorial Health System in Colorado Springs CO

  2. This is the response I gave to our staff in response to their concerns about JCAHO and blanket warmers.
    Since that time, 3 years ago, we have replaced out blanket warmers with the newer cabinets with the digital temp display of cabinet temperature. Blankets are kept at a cooler temp because of this. I still believe that staff are able to determine appropriate blanket temperature without these expenseive warmers. As far as I am aware no one ever identified a pattern of injury in the use of blanket warmers. This demonstrates how Healthcare cost is driven up without adequate study to determine if this is a real need.

    “The rationale regarding blanket warmers is this:
    Those older blanket warmers are not intended to be managed by a door mounted thermometer which cannot really determine what the average temperature of the blankets within is at. They were built to be managed by the temperature knob that they have. The ECRI guidelines recommend a maximum temperature for blankets, which is a guideline, not a performance standard. Therefore the decision was made that managing the older blanket warmers with add on thermometers was not appropriate and we should not be logging the temperature of blankets because there is not a requirement to do so. However staff needs to be aware of what the recommended maximum safe temperature for blankets is. Since our Risk History does not indicate we are having problems with blankets being used that are injuring patients we feel that the caregivers have been managing blanket temps adequately. As we replace with the newer version blanket warmers we will be more confident in the temperate setting on the cabinets. I hope that helps.”

  3. Scott Wallask

    I like Al’s approach. Just my opinion, but that would seem to satisfy the idea of a risk assessment for blanket warmer temperatures, too, because clearly there’s consideration of the options and the facility acted on what it felt was the best choice.

  4. We are pending Joint Commission survey at any time. When the Joint Commission is here we are considering discussion of a pending risk assessment to the Joint (for their opinion) as follows:

    Use a hi/lo tracking digital temperature guage with a probe inserted inside a blanket in the warmer. monitor high and low temps for let’s say a week to establish trends.

    Consider allowing the temp set on the warmer to be higher than 110 degrees F if it can be demonstrated that the blanket temperature does not exceed 110.

    Any flaws in this proposed study?


  5. Steve MacArthur

    It’s interesting how the most basic of topics can get the telegraphs working.

    I’m (sort of)responding to everyone who has suggested various and sunry strategis for managing this particular device (and actually, this equally applies to any “risk” for which there is no specific regulatory requirement).

    The “glory” (and the curse) of the risk assessment process is that there is not correct or incorrect strategy so long as you can back up your decision with either performance data or at least a logic train that will withstand some scrutiny. For instance, in the case of the blanket warmer temps, you might decide that based on your environment, the distance between the warmer and the patient, perhaps with a consideration of skin integrity isseus within your patient population, you might determine that a 10% increase in holding temperature can be maintained without an increase in risk (that puts it at about 120 degrees F). So long as you have a clear decision process, that should more than suffice. However, if you have some outliers that want to jack things up too far beyond that 10% margin, then you get jammed on filing to comply with your own policy. Ultimately, it’s all about outcomes – if you’re not having skin issues with your patients and you have good compliance, then you’re doing what is necessary to appropriately manage the risk.

    Quick note to Tim – I don’t see a flaw in the study, but one thought relative to the Joint Commission surveyors – I don’t know that I’d ask their opinion on what you’re doing (as much because you need to have thte courage of your convictions, or in this case, the courage of your assessment). The expectation is that each organization makes decisions based on their specific set of circumstances and so the risk management strategy should be reflective of those circumstances. You might ask the surveyors if they’ve seen any innovative approaches to managing this risk (I haven’t run into anything truly innovative – maybe we’ll hear from someone who’s got something really funky to share) or you might just make the determination, educate staff and pride yourself on a job well done (I like the latter as it involves the most “self’control” over the process.

    I hope this helps and (here comes the commercial) I hope to see each and every one of you in Vegas in May for some heated blanket discussion.

    Steve Mac.

  6. I, too, have been perplexed about temperature settings on blanket warmers. Current studies dictate temperature settings for devices that include BOTH fluids and blankets. The most recent study I read, which makes the most sense, was published by Dr. Moo, a biomedical engineer (www.Devicix.com). He states that even heating a cotton blanket to 200 degrees F will only increase the patient’s body temperature by 1.4 degress Farenheit. For our post-op patients, who are usually freezing, we have set our blanket warmer (does not contain fluids) to 160 degrees F. We have not burned anyone. Blankets cool substantially when removed from the warmer before it is placed on the patient. I completely understand the pause and rationale about not setting your warmer temperature above 110 degrees F for those warmers that contain fluids. Research has shown patient burns when fluids have been kept at 120 degrees and above. This makes sense, but not for blankets only. My thoughts.

  7. We did a study in all of our units and measured blanket temperatures upon removal from the warmers and upon reaching the patient. We found that blanket temperatures dropped extremely rapidly after being removed from the warmers. This study and documentation has allowed us to safety increase the temperature of our warmers and still prove that the blankets do not exceed 110 degrees when they reach the patient.

  8. Good job Julia!

    We handled the issue in classic safety style- engineering controls. All of our warmers are limited so they cannot go above 110 for blankets and 104 for fluids. A simple and effective fix.

  9. Ok, now to throw a spin on this. What about items like the ready bath moist towels? The Sage version comes with a warmer that is set at 125+-5? That would stay warmer in transport to the patient than a dry cloth blanket. This could be looked at for the microwave type ready bath towels also. How is temp being checked or equipment recomendations to alter temp on these type moist patient towels?

  10. Linda, what study are you referring to by Dr. Moo. I am not having success finding. I am trying to gather all of the “proof” that I can that 110 F is not appropriate.


  11. I am a home inventor who wandered into your discussions while researching the subject. The original (and still valid) objective is to provide to a bedridden person thermal comfort by gently blowing from a bedside unit either hot or cold air through the blanket’s micropores. This invention will of course be attractive to the general population for one can sleep in comfort without having to heat or to air-condition the whole house. My product is meant to be affordable to anyone and will cost pennies to run (<300 watts.)

    My question here is what will be the steady temperatures hot or cold) required for your applications?

    1. If the heated blanket comes out of the oven at 110 degF I presume it will cool down fairly fast and needs to be replaced with another warm blanket. At what lowered temperature do you deem it prudent to replace the blanket. That is at what steady temperature should I set my device?

    2. For a patient with a fever what will be the cool temperature you would maintain the patient in? Or for a healthy person how many degrees below room temperature should I aim for to provide a comfortable sleep?

    Thank you.

  12. As part of the E of C committee for an academic medical center, I received their latest warming cabinet protocol yesterday calling for max temps of 120 for blanket warming and 105 for fluids based on the 3 following references:
    1-ECRI, April 2007
    2-Healthcare Purchasing News, Dec 2004 – article by Jeannie Akridge “Turning Up the Heat on Temperatures and Pressure Management”
    3-AORN Journal article on Saline Warmers Oct 2007.

  13. Ms. Campbell…..was wondering if your internal study results are available for others to review. I’m just an office-based surgeon currently shopping for 3 new blanket warmers…and stumbled across this blog. Your idea seems most applicable to our type of practice.

    I have a feeling that I may be starting to type….yep, here it comes….a long, somewhat facetious message providing constructive critism for ECRI; their cavalier use of the term “evidence-based;” their recommendations and very bold statements on their website–both of which appear to be pervasively-based on the presumption that “common sense” does not exist; etc. etc. Admittedly, I don’t work in a hosptial setting, or with “insensate” patients…and I definately support the concept of “preventative assessment”; but, their recommendations should not become “general practice guidelines” for the health-care field. They simply are saying that (loosely paraphrasing) ‘we’ve seen documented cases of patient burns related to warming blankets….so we turned down the warming unit temperature until we saw no risk of burns….so everyone should turn down their blanket warmers to this upper-safe limit.’ Most warming blankets are really not used “therapeutically” (i.e. for correction of hypothermia, etc.), but rather for “comfort.” We want to make a patient’s experience as least unpleasant as possible, and it’s amazing how many unsolicited comments we get about the “warm blankets” being “wonderful.” We similarly set our units to 160-180 degrees….where the folded blankets definately feel “hot” to touch (but not painful) when you pull them out…then we walk about 30-50 feet (depending on the surgery room), open the blanket, and drape it over the patient…..we’ve never had a burn, and have never had a patient say “ouch/too hot.” We intermittently confirm (via thermometer) that the units’ temperature reading are “true.” And even with 160-180, we commonly find that patients “would like” another “fresh one” within 15-20 minutes. So, I think ECRI should promote a new “guideline” for “sensate” patients; something to the effect of ‘if one does not have to wear an oven mit to remove said blankets from said warmer; if one uses concept of “common sense;” and if one opens blanket, drapes atop patient, then inquires whether or not blanket is “too hot,” and immediately removes blanket if patient responds affirmatively; then one is providing maximum patient comfort with negligible risk of unintentional thermal injury to said patient.’

    Julia–really I was just interested in the numbers/data that you came up with….and chance of getting those for reference?

  14. We conducted a rather extensive study of blanket temperatures. You may consider our results.

    We tested a variety of locations: e.g., Cath Lab, PACU, Specials
    Results varied if the warmer was full or partially full.
    Results varied if the warmer was accessed after sitting all night vs used throughout the day. (With the warmer set at 140 degrees blankets located nearest to the heating element were showing temps of 172 to 182.)

    Using 6 different times of day (even hours), with the warmer set at 140 and room temp at 72.8, the average blanket temp was 174.
    Immediately upon opening the blanket the avg temp dropped to 120. If we shook the blanket the avg temp was 115
    After 15 sec the temp was 105, with shaking 100
    After 30 sec the temp was 89, with shaking 100
    After 45 sec the temp was 83, with shaking 92
    We did 5 sec intervals …. same results
    At 105 sec the temp was 78, with shaking 78.

    Conclusion: Patients were most satisfied with blanket warmth at 110 degrees. In order to have the temp be 110 degrees by the time it reached the patient our warmer had to be set at 140-160 degrees. We used two diffeent brands of temperature probes to do the measure. We are confident we can defend keeping our warmers at 140-160 degrees.

  15. Barbara,
    Can you please the articles you found. Thank You, Cory

  16. Janel, I am too looking for supportive literature on raising the blanket warmer temperature for the Pre and Post OP patients. 110 degrees is just not warm enough.

  17. Marilyn,
    I would like to see your full study. The research committee at my hospital brought this topic up because we have issues with compliance with keeping temps of warmers at 110. This is because they do cool off so fast that the blankets are not warm enough to help increase patient’s comfort and warmth.
    Thanks for your help.

  18. I was doing some searching on blanket warmer temps in preparation for a meeting at a large academic hospital where I plan to argue for a higher temp than the current 110 degree hospital policy. Just discovered that ECRI haas retracted – they know recommend a max temp of 130 degrees for blanket warmers, but remind us not to put fluids in such warmers. Thank you ECRI! see http://policy.cdha.nshealth.ca/default.aspx?page=53&class285.Id.0=13453&class286.Id.0=13453

  19. We have been fighting this temperature battle since 2005, when ECRI erroneously recommended a max of 110F for blanket warmers, which they have since been raised to 130F. The key to the discussion and the science is found in the physics. A cotton blanket which is 50% air cannot hold and thus transfer enough heat (due to cotton’s low specific heat) to cause a thermal injury to the patient. Please see the article by Dr. Moon at http://www.enthermics.com. to get the physics facts. In addition, our most recent study of 100 patients, receiving 200F blankets further validates the science. http://www.enthermics.com/learn/pdfs/Blankets_Warmed_to_200F.pdf

    The problem is and always has been the danger of overheating FLUIDS. Unlike cotton, fluids have a very high specific heat or ability to hold and transfer heat. This is where the danger lies, not with cotton blankets.

    Consider this, the average household clothes dryer operates at around 350F and all of us have pulled our clothes straight out of the dryer and held them to our skin and said “that feels good”. And none of us have been burned.

    The simple solution is what we at Enthermics have been saying for 20 years, use separate warmers for blankets and fluids. “Warm blankets in a blanket warmer, all the way up to 200F”. “Warm FLUIDS in a FLUID warmer at the appropriate lower temps recommended by the fluid manufacturer”. “And never warm fluids in a blanket warmer”, (this is where the danger lies).

    Feel free to contact me for further information;

  20. The article is posted on the website http://www.enthermics.com and the author is Dr. Moon. It is a discussion of heat transfer physics and the inability of cotton to transfer enough heat to the skin to cause any injury.

  21. I appreciate the discussions previously submitted. Any new thoughts for 2011? I am currently advocating for a return to 160 degree set point for our blanket warmer. Now that it has been turned down to 130 degrees, blankets are only lukewarm. There really seems little point to using the “blanket warmer”.
    I have not been able to find any instances of patient injury due to a warm cloth blanket. Am I missing some research that shows injuries have occurred? If not, I’ll keep working with Dr Moon’s information to try and change our policy.

  22. I work in adult open heart surgery and the difficulty we are having related to fluid temps is that in a room that is set at a temperature of, say 65 F, fluids that are supposedly warm at a temp of 104 F cool off extremely rapidly once decanted onto the field. This is not fluid administered IV, but used topically. I haven’t seen any data that indicate what temperature is safe for topically applied fluids. When fluids were kept at a higher temperature, the advantage was that we were able to utilise the fluid for a longer duration before it cooled off. Does anyone know if fluid temperature guidelines apply to topically applied, IV fluids or both?

  23. Catherine,

    I do not believe there is any distinction for topical solutions. As previous noted by other, warming cabinets used to heat solutions should be limited to 110° F (43°C), pursuant to ECRI, which is supported by AORN (See:http://www.aorn.org/Clinical_Practice/Clinical_Answers/Environment_of_Care.aspx) and ASPAN (See: http://www.aspan.org/ClinicalPractice/FAQs/tabid/9150/Default.aspx#blanket)

    If you are interested in On-Demand Irrigation Fluid Warming, please visit our website at http://www.thermedx.com, or contact me at mharitakis@thermedx.com, to learn more about our Irrigation Fluid Management System that includes warming. Thank you.


  24. We are now in 2018 what are the maximum temperature settings for blanket warmers? Our Steris/Amsco specs indicate the max temperature to 160 degrees, Getinge is also 160 max, and Olympic-Warmette is limited to 150.
    ECRI Institute recommends that temperature settings on blanket warming cabinets be limited to 130℉ (54℃) and that solution warming cabinets be limited to 110℉ (43℃). AORN recommends a limit of 130ºF for blankets and to be in accordance with solution manufacturer recommendations regarding specific solutions. Is there still no nationally recognized standard for blanket warmer temperatures?

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